Add overridable method "setup" for defining properties

libraries/scripting/common/src/kotlin/script/experimental/api/propertiesDsl.kt

@@ -33,6 +33,8 @@ open class ScriptingProperties(body: ScriptingProperties.() -> Unit = {}) {
         body()
     }
 
+    open fun setup() {}
+
     internal fun makePropertyBag(): ChainedPropertyBag =
         ChainedPropertyBag.createOptimized(parentPropertiesBag ?: parentPropertiesBuilder?.makePropertyBag(), data)
 

libraries/scripting/common/src/kotlin/script/experimental/definitions/definitionFromAnnotation.kt

@@ -61,7 +61,7 @@ fun createScriptDefinitionFromAnnotatedBaseClass(
     }
 
     fun scriptingPropsInstance(kclass: KClass<out ScriptingProperties>): ScriptingProperties = try {
-        kclass.objectInstance ?: kclass.createInstance()
+        kclass.objectInstance ?: kclass.createInstance().also { it.setup() }
     } catch (e: Throwable) {
         throw IllegalArgumentException(ILLEGAL_CONFIG_ANN_ARG, e)
     }